Railway-traffic-controlling apparatus



LI L. NETTLETON ET AL d RAILWAY TRAFF'IC CONTROLLING APPARATUS Filed oct.

Patented Aug. 9, 19727.

UNITED STATES PATENT orricaj LEWIS L. NE'ITLETON, or nDGEWoon BOROUGH, AND LARs o. .GRoNDAHn oF PITTS- BURGH, PENNSYLVANIA, AssIeNons To THE UNION SWITCH & SIGNAL COMPANY,

OF SWISSVALE, PENNSYLVANIA, A CORPORATION lOF' PENNSYLVANIA.

RAllLWAY-TRAFFIC'-CONTROLLING` APPARATUS.

Application filed October 22,1926. Serial No.'143,379.

Our invention relates to railway traflic controlling apparatus, and `particularly to apparatus of the type wherein alternating current is periodically supplied to the track rails vfor the control of traffic governing mechanisinwhich is responsive to such periodic supply of alternating current but not to the continuous supply of such current.

One form of apparatus ofthe character referred to is disclosed and claimed in application for Letters Patent of the United States tiled by C. S. Snavely on May 29, 1926, Serial No. 112.491. In the apparatus disclosed in that application; when a. section is occupied by a train and the next section in advance is unoccupied, alternatingr currents of two different frequencies are alter- .nately applied to the track rails, and the train-carried apparatus is tuned to respond to onel of these currents but not` the other. This tuning is usually accomplished by an electric filter, but we have found thatV under some conditions the filter may respond to what we term shock excitation, that is, when an alternating current is suddenly applied at its full value to the track rails. the filter receives an impulse whichvcauses it to oscillate and so to falsely apply voltage to the train-carried apparatus, and this may be true even though the current which is abruptly applied is the current to which the filter is not tuned.

@ne feature of our invention is the provision of means for preventing sudden application of current' to the track rails, that is, means for lowering the rate of increase of the current to .its full value when the current is applied.

kllVe will describe one form of apparatus embodying our invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form of apparatus embodying our invention.

Referring to the drawing, the reference characters 1 and 1a designate the track rails of a railway along which traiiic normally moves in the direction indicated bythe arrow. These rails are divided into track sections Of which only one section C-D is shown in the drawing. Located at the exit end of section C-D are two transformers E and E100, the secondaries 11 and 9 of which are connected in series across the rails 1 and 1a. The primary 10 of transformer E00 isat times supplied with alternatingsignaling currentfrom the secondary 12 of Aa transformer T00, the primary 13 of which is constantly connected with a source of alternating current which is not shown in thedrawing. Similarly, the primary 8 of transformer E100 is at times supplied with alterhating current from the secondary 14 of a transformer T100, the primary 15 of which is constantly connected with a source of alternating current not shown in the drawing. The currents supplied-to the transformers T differ in frequency, and, as an example. the current supplied to transformer T00 may be 60 cycles per second, and the current supplied to transformer T100 may be 100 cycles per second.

The supply of current to the transformers F. is controlled by a relay G, which we will term a coding relay, andthis relav is in turn controlled by a track relay F which is connected across the rails at the entrance end of section Chl) and is responsive to the 6U cycle current supplied to these rails by transformer E00. The coding relay G is provided with a circuit which passes from terminal B of a suitable source of current through back contact 8 of track relay FQ winding of relay G, and back Contact 4 of relay G to terminal O of the same source of current. It will be seen, therefore, that when section C-D is unoccupied and track relay F is energized, relay Gr will be at rest in its cle-energized condition, but that'when track relay F is cle-energized the coding relay G will be alternately energized and deenergized, due to the fact that its back contact 4 is "included in the circuit for this winding.

The reference character H00 designates a thermo-sensitive relay having a heating element 6 and a thermo-sensitive clement 7. The thermo-sensitive elementi' is included in the primary circuit for transformer E00. The reference character H100 designates a similar thermo-sensitive relay, the thermosensitive element 7 of which is included in the primary circuit for transformer E100. The heating element 6 of relay H00 is provided with a circuit which includes a battery 16 and a back contact 5 of the codinv relay G; the heating element 6 of relay H9100 is provided with a similar circuit'. which includes the battery l@ and the ti'oifit Contact :3 et' coding; relay G.

The parts are soadjusted that whenV the heating element. 6 of either. relayv H is deenergized. th ev thermofsensitiye. element. 7 is oit such high resistance that substantially no current is suppliedtothe primary of the associated transformer E, whereas,'when the heating' eement 6 of either relay H. isenergized, the resistance ot 'the thern'io-sensitiveelement 7 o'ly sucli relay'is" re'ducedf' to such` valueft'hat current otan opeiatin ralue supplied'fto the cssociatedtransformer` E.

Normally when the sectioni G-D is un occupied, .so-that coding"relay.` (if: is at rest'7 the heating: element G' otrelay'lflto 'is-'energized'so' that 60' cycle' Acurrent-t is'l supplied toitrans'former'E90, and. this current in the tra-cl; rails ofsecti'on GQ-D'holds the track in' its energized" condition. llilhen' a traiir entf-.irs` section' C-D'.. however-5. the opening; o'lrelay F causes periodicr opera tion'. of= the-coding'relay. @Veo that the heatingf elements Goff the relays H90" and Hm arei alternately energize... with the result that cycle/current' and 10fcycle current are' alternately supplied to the tinck rails through t-he transformers EN and Em" re` spectively. Each time that the front4 er'the back' ccifitact on t-:heiA coding.A relay` clcses, the' heating; eemen't of' one of" the relays H hecomesv energized: but al time interval is required 'for' thel thermoesens-itive element of' such relayt'oi become heatedi toiteulti'- mate' temperature,I and). consequentiy,'. av. time intera/alfy is; required for 'the' alternating current supplieda through such relay' to build uptof its ultimate Value; Thistimei inter ual* may,' 'for' example; beethe'time required 'for' approximately five cycles`I oli GO' cyce current'. '.Dhisslow bnilfdingcnp of the current' applied toth'e track. railsprevents sud'- den excitation ot the il'ter or other tuning` de vice' whi ch receives currentl Jfrom f the track rails,1 anda consequently. eliminates the tram sientf impulse which. is 'likelyto' pass throu gli the filter if currentA isinstantaneouslyx applied to thel track raiisat its 'full Value.

Although we'hawek herein' showin anda de scrihedonly one tormfof apparatus embody.L ing our invention, it is understood that vari'- ous changes. and" modifications may be .made therein within the scope' ot the appended claims'without departingffi'om the spirit and scope of our invention..

y l-laving` thusV described our'inVent-ion; what lowering' the rate oi" increase and"decreaseV oli' suclr current in. the. track rails.

2. ln railway traliic controlling' apparatus ofA thefty-pe comprising` means `tor periodically supplyiin;` current to theV track rails the combination therewith: oi .means 'for causing the current in the'tradorailsfttrbuiltl` up slowly each time it is' supplied? tothe rails. i i 'i 3'.' In railway tratlic controlling` apparatus ot the typey comprising' meansr fon periodiically supplying'current' to the track rails', the combination. therewith oi' means for low:- ering tlie rate ot increase of'such current" in the tracky rails.

Lt. in railway traiic controlling appara.:- tus ofA the type comprising means for periodi lly supplyingl current to the traclt rails, the combinationtherewith ol means 'l'or'pref renting sudden increase or' the current in the track iail'i. Y

5. In'conibiznitionV with the traclcrails'oa railway and a source oi' current' connected therewith. means interposed betweenl said source and a track rail foi-:periodical l y ingg'the value oi. the current suppliedtoit. rails and for preventing sudden` change' in such value.

62 ln combination with the track: raiis'- oi' Vivai a railway. a source of current connected with said rails tliroutrl'i atheiimtreeusitiue substance7 a heating' ele-ment forivaryingthe temperature et" said" substance. and ac-ircuit 'tor said. heating element includingv a periodL icalty operating' Contact..

i". 'In combination with the track-:rails of a railway, a source ot' afternating7 current ol one frequency connected with! said railsV through'. a''thermo-sensit'ive substancg aiseeond source of alternating'current otf'a'; dif'- terent "frequency` connectedwitlr said! rails vtl iron gli a1 second l thermosensitivel substance;

a heating' element for each ther-moesensitiye substance and: means-.for alternately#supplymy; current to-saith heating` elements-L 'In testimony whereof4 we athis( our signa#V tures.

Lewisl L.. narranToit.l Lans o; encaminar.; 

